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參數資料
| 型號： | FA3647N |
| 廠商： | FUJI ELECTRIC CO LTD |
| 元件分類： | 穩壓器 |
| 英文描述： | PWM control IC with light load power saving function For Switching Power Supply Control |
| 中文描述： | 1 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封裝： | SOP-8 |
| 文件頁數： | 13/21頁 |
| 文件大小： | 406K |
| 代理商： | FA3647N |
FA3641P(N), FA3647P(N)
70
Fig. 19 Startup circuit (1)
Fig. 20 Startup circuit (2)
2. Deciding the startup circuit
These ICs, which use CMOS process, consume less current,
and therefore can use larger startup resistance than the
conventional bipolar type of IC.
To decide the startup resistance, the following conditions must
be satisfied:
(a) The IC is started when the power is turned on.
(b) The IC consumption current is supplied during latch
mode operation to maintain the latch state.
(c) The IC consumption current is supplied during the off state
under the on/off function to maintain the off state.
However, these are the minimum conditions for using the IC.
The startup time required for the power supply must also be
decided on.
2.1Connecting a startup resistor before rectification
(AC line)
When the startup resistor is connected before rectification (AC
line) as shown in Figure 19, the voltage applied to the startup
resistor forms a half-wave rectified waveform of the AC input
voltage.
Startup resistor R1 must satisfy the three equations shown
below. Select a smaller-side value for R1 in consideration of the
temperature characteristics.
(a) To supply startup current 30
μ
A at ON threshold voltage
17.5V (max.) of UVLO:
2
Vac
–
17.5
R1 [k
] <
π
0.03
........................................ (8)
(b) To supply IC consumption current 100
μ
A (max.) (Vcc =10V)
in latch mode:
2
Vac
–
10
R1 [k
] <
π
0.1
....................................... (9)
(c) To supply IC consumption current 200
μ
A (max.) (Vcc =17V)
in the off state under the on/off function:
2
Vac
–
17
R1 [k
] <
π
0.2
......................................(10)
R1:
Vac: Effective value of AC input voltage [V]
Startup resistance [k
]
If neither the latch mode operation nor the on/off functions are
used, only the expression in (8) needs to be satisfied.
In this method, the supply current to the IC via the start-up
resistor is stopped when AC input is shut down. Therefore, after
latch mode operation, shutting the AC input down resets the
latch mode in a very short period of time.
2.2 Connecting the startup resistor after rectification
(DC line)
When the startup resistor is connected after rectification (DC
line) as shown in Figure 20, the voltage applied to the startup
resistor becomes the peak value of the AC input voltage.
Startup resistor R1 must satisfy the three equations shown
below. Select a smaller-side value for R1 in consideration of
temperature characteristics.
(a) To supply startup current 30
μ
A at ON threshold voltage
17.5V (max.) of UVLO:
..................................(11)
R1 [k
] < 2
Vac
–
17.5
0.03
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PDF描述 |
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| FA3647P | PWM control IC with light load power saving function For Switching Power Supply Control |
| FA365 | THIN SMD HIGH-FREQUENCY CRYSTAL UNIT |
| FA-365 | THIN SMD HIGH-FREQUENCY CRYSTAL UNIT |
| FA3675F | For Switching Power Supply Control |
| FA3863X | SUPER BRIGHT LED |
相關代理商/技術參數 |
參數描述 |
|---|---|
| FA3647N-H1 | 制造商:Fuji Electric 功能描述: |
| FA3647P | 制造商:FUJI 制造商全稱:Fuji Electric 功能描述:PWM control IC with light load power saving function For Switching Power Supply Control |
| FA3647P-D1 | 制造商:Fuji Electric 功能描述: |
| FA365 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:THIN SMD HIGH-FREQUENCY CRYSTAL UNIT |
| FA-365 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:THIN SMD HIGH-FREQUENCY CRYSTAL UNIT |
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